Agnieszka Iwanowska, Edward Pospiech

The aim of the paper was the comparison of slaughter value and muscle properties of dual-purpose cattle most common in Poland with that of beef type, from which high quality culinary meat is obtained. Four breeds were compared: two of them were dual-purpose type i.e. Holstein-Fresian of Black and White variety and Polish Red and the other two – of beef type i.e. Limousine and Hereford. There are discussed factors influencing cattle slaughter value and muscle properties, i.e. the impact of the utility type, gender, age, feeding systems, as well as maturation rate of animals. The slaughter value was presented using the dressing percentage and the content of main components in the carcass i.e. the muscle tissue, fat and bones. The tissue composition of analysed cattle breeds and the share of main cuts in their carcasses were presented. Higher daily gains of beef type or dual-purpose breeds are connected with a higher number of muscle fibers (hyperplasia) and also with a bigger size of their diameter (hypertrophy). These phenomena are accompanied by increased lightness of meat colour what is the result of changes in the muscle fibers metabolism and the proportion of myosin heavy chains (MHC) of the I, IIa and IIx type. Observed differences in the slaughter value existed not only between breeds, but also inside them indicating the need for further improvement of animal selection and deeper analysis of factors influencing it. It was stated that the amount of culinary meat obtained from carcasses may be increased not only through the selection of corresponding genotypes, but also through the modification of the system of carcass cutting. The performed analysis of the slaughter value emphasizes special significance of the domestic Polish Red cattle also as a breed for production of good quality meat similar to beef cattle breeds.